N-acetyl cysteine and selenium protects mercuric chloride-induced oxidative stress and antioxidant defense system in liver and kidney of rats: a histopathological approach

Current Progress in Gallium-based Liquid Metals for Combinatory Phototherapeutic Anticancer Applications

A variety of therapeutic approaches using liquid metal (LM) have been intensively investigated, due to its unique physico-chemical properties that include high surface tension, fluidity, shape deformability, thermal conductivity, and electrical conductivity. Among a series of LMs, the relatively lower toxicity and minimal volatility of gallium (Ga)-based LMs (GaLMs) enables their usage in a series of potential biomedical applications, especially implantable platforms, to treat multiple diseases. In addition, the highly efficient conversion of light energy into thermal or chemical energy via GaLMs has led to recent developments in photothermal and photodynamic applications for anticancer treatments. As attractive photothermal agents or photosensitizers, a systematic interpretation of the structural characteristics and photo-responsive behaviors of GaLMs is necessary to develop effective anticancer engineering applications. Therefore, the aim of this review is to provide a comprehensive summary of currently suggested GaLM-mediated photo-therapeutic cancer treatments. In particular, the review summarizes (1) surface coating techniques to form stable and multifunctional GaLM particulates, (2) currently investigated GaLM-mediated photothermal and photodynamic anticancer therapies, (3) synergistic efficacies with the aid of additional interventions, and (4) 3D composite gels embedded with GaLMs particles, to convey the potential technological advances of LM in this field.

Antagonistic effect of selenium on mercuric chloride in the central immune organs of chickens: The role of microRNA-183/135b-FOXO1/TXNIP/NLRP3 inflammasome axis

Mercury (Hg) is a persistent environmental and industrial pollutant that accumulated in the body and induces oxidative stress and inflammation damage. Selenium (Se) has been reported to antagonize immune organs damage caused by heavy metals. Here, we aimed to investigate the prevent effect of Se on mercuric chloride (HgCl₂ )-induced thymus and bursa of Fabricius (BF) damage in chickens. The results showed that HgCl₂ caused immunosuppression by reducing the relative weight, cortical area of the thymus and BF, and the number of peripheral blood lymphocytes. Meanwhile, HgCl₂ induced oxidative stress and imbalance in cytokines expression in the thymus and BF. Further, we found that thioredoxin-interacting protein (TXNIP) and the NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome mediated HgCl₂ -induced oxidative stress and inflammation. Mechanically, the targeting and inhibitory effect of microRNA (miR)-135b/183 on forkhead box O1 (FOXO1) were an upstream event for HgCl₂ -activated TXNIP/NLRP3 inflammasome pathway. Most importantly, Se effectively attenuated the aforementioned damage in the thymus and BF caused by HgCl₂ and inhibited the TXNIP/NLRP3 inflammasome pathway by reversing the expression of FOXO1 through inhibiting miR-135b/183. In conclusion, the miR-135b/183-FOXO1/TXNIP/NLRP3 inflammasome axis might be a novel mechanism for Se to antagonize HgCl₂ -induced oxidative stress and inflammation in the central immune organs of chickens.

Sexual dimorphism in inorganic mercury toxicokinetics and the attendant lipotoxic and non-lipotoxic dyslipidemia in the rat

The influence of variability in the biology of living organisms is poorly appreciated in toxicology. However, multiple lines of evidence indicate that sex-differences modulate toxicokinetics and toxicodynamics from cellular/molecular to whole animal levels resulting in different toxic responses of living organisms to xenobiotics exposure. In order to investigate the influence of sex in inorganic mercury (Hg) exposure, male and female Wistar rats were exposed to 0.5, 1.0 and 1.5 mg Hg/kg body weight orally as HgCl₂ twice a week for 12 weeks. Higher Hg levels in the females (except heart) as compared to males were observed in the animals. At the highest dose of inorganic Hg, female renal Hg content was 3.3 times higher than that of the males. Mixed sexual dimorphism characterised circulating-lipid- and organ-lipid lipotoxic and non-lipotoxic dyslipidemia. The highest dose of inorganic Hg, induced hypercholesterolemia in the males as opposed to hypocholesterolemia in the female. Plasma and erythrocyte free fatty acids increased in both sexes, although the increase was more pronounced in the male. Reverse cholesterol transport was inhibited in the male at the highest dose of Hg, whereas female HDL became enriched with cholesterol. Female erythrocytes had all their lipids increased, whereas only male erythrocyte triglyceride increased. Brain cholesterol and phospholipids, and splenic phospholipids were depleted in both sexes. Our findings indicate that inorganic Hg exposure appears to affect Hg and lipid kinetics differently in both sexes, thus underscoring the need to develop sex-tailored approaches in the treatment of metal toxicosis and its metabolic outcomes.

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The influence of sex in inorganic Hg exposure was investigated in the rat.

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Higher Hg levels in females compared to males were observed.

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Sexual dimorphism characterised inorganic Hg-induced dyslipidemia.

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Inorganic Hg exposure affects Hg and lipid kinetics differently in both sexes.

The Antioxidant Efficacy of Wheatgrass (Triticum Aestivum) on Mercuric Chloride (HgCl2) - Induced Oxidative Stress in Rat Model

Mercury is a harmful toxic pollutant, which has hepato-nephrotoxic, hematotoxic, genotoxic and neurotoxic, effects. The aim of the study was to evaluate the protective efficacy of wheatgrass on mercuric chloride (HgCl2) induced oxidative stress and associated complications in rat model. Albino rats were divided into four groups (three rats per group). Group I normal control group. Group II oxidative stressed group received mercuric chloride (0.5 mg/kg/day). Group III only received wheatgrass extract (100 mg/kg/day), whereas Group IV received wheatgrass (100 mg/kg/day) after one hour, followed by mercuric chloride (0.5 mg/kg/day) for 30 days. The results of the study showed that wheatgrass supplementation significantly decreased the HgCl2 induced elevated oxidative stress parameters Plasma Malondialdehyde (MDA) content, Plasma membrane redox system (PMRS), Advanced oxidation protein products (AOPP), simultaneously elevated lipid profile (Total Cholesterol, Triglycerides, Low-density lipoprotein (LDL), liver enzymes as, Plasma Alkaline phosphatase (ALP), Aspartate aminotransferase (AST), and Alanine aminotransferase (ALT), Serum Urea, and Creatinine levels in rats. In addition, wheatgrass treatment improved the antioxidant status in terms of intracellular Reduced Glutathione (GSH), Ferric reducing antioxidant power (FRAP) and 2, 2- diphenyl -1- picrylhydrazyl (DPPH). Therefore it can be concluded that wheatgrass has great potential to diminish the stress-mediated complications and improve the antioxidant status.

Cr (VI) induces abnormalities in glucose and lipid metabolism through ROS/Nrf2 signaling

The hexavalent form of chromium, Cr (VI), has been associated with various diseases in humans. In this study, we examined the mechanisms underlying the effect of Cr (VI) on glucose and lipid metabolism in vivo and in vitro. We found that Cr (VI) induced abnormal liver function, increased fasting blood glucose (FBG), as well as glucose and insulin intolerance in mice. Furthermore, Cr (VI) decreased glucose-6-phosphate (G6P) level and glucose transporter-2 (GLUT2) expression, increased the levels of triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), reduced high-density lipoprotein-cholesterol (HDL-C), and increased sterol regulatory element-binding proteins 1 (SREBP1) and fat synthase (FAS) in vitro and in vivo. Moreover, Cr (VI) promoted intracellular ROS production in vitro, and induced reduction of antioxidant enzyme level and Nrf2/HO-1 expression in vitro and in vivo. Also, N-acetyl cysteine (NAC, effective antioxidant and free radical scavenger) pretreatment inhibited the production of intracellular ROS, significantly suppressed Cr (VI)-induced oxidative stress, lipid accumulation, decreased G6P and GLUT2, and improved impaired glucose tolerance and glucose and insulin intolerance caused by Cr (VI) in mice. Dh404 activated expression of Nrf2 decreased ROS level, increased HO-1 expression, ameliorated activity of the antioxidant enzyme, inhibited Cr (VI) increase of SREBP1, FAS level, and reduction of G6P and GLUT2. To sum up, these data suggest that dysregulation of ROS/Nrf2/HO-1 has an important role in Cr (VI)-induced glucose/lipid metabolic disorder.

The human health risks assessment of mercury in soils and plantains from farms in selected artisanal and small-scale gold mining communities around Obuasi, Ghana

Food consumption remains the commonest pathway through which humans ingest higher levels of mercury (Hg). Long-term exposure to Hg through Hg-contaminated food may result in acute or chronic Hg toxicity. Incessant discharge of Hg waste from ASGM facilities into nearby farms contaminates food crops. Ingestion of such food crops by residents may lead to detrimental human health effects. The human health risks upon exposure to total mercury (THg) and methylmercury (MeHg) in farmland soils and plantains from farms sited near ASGM facilities were studied in four communities around Obuasi, Ghana. The human health risk assessment was evaluated using hazard quotient (HQ), estimated average daily intake (_e AvDI), hazard index (HI) and Hg elimination and retention kinetics. Tweapease, Nyamebekyere and Ahansonyewodea had HQ, _e AvDI and HI for THg of plantains for both adults and children below the recommended USEPA limit of 1, 3 × 10^-4  mg/kg/day and 1, respectively. Odumase had HQ, _e AvDI and HI for THg of plantains for both adults and children, higher than the guideline values. This meant that only Odumase may cause non-carcinogenic human health effects upon repeated exposure. The HQ, _e AvDI and HI values of MeHg for all the study areas were far below guideline values, hence may not pose any non-carcinogenic human health risks to residents even upon repeated exposure. Retention and elimination kinetics of Hg also showed that only plantains from Odumase may pose significant non-carcinogenic human health risks to residents because the final amount of inorganic mercury exceeded the extrapolated USEPA guideline value of 0.393 μg/kg/year.

Vitamin E and Lactobacillus Provide Protective Effects Against Liver Injury Induced by HgCl2: Role of CHOP, GPR87, and mTOR Proteins

BACKGROUND AND OBJECTIVE

Mercury is one of the most harmful heavy metals and its toxicity causes severe multi-organ dysfunction. This study was designed to explore novel molecular pathways involved in the hepatoprotective effect of vitamin E (Vit-E) and Lactobacillius plantarum (Lac-B) against mercury toxicity.

METHOD

Acute hepatotoxicity was induced by administration of high dose of mercuric chloride (HgCl2) in male rats, Vit-E or/and Lac-B were given along with HgCl2 for 2 weeks. The effects of those antioxidants were studied focusing on their anti-apoptotic, anti-oxidative stress and anti-inflammatory eficacies. Histopathological examinations were also conducted.

RESULTS

The administration of HgCl2 induced liver injury which manifested by elevation in serum ALT and AST. Liver MDA, caspase-3 and TNF-α levels were markedly increased; whereas, GSH level and SOD activity were declined. HgCl2 significantly elevated the expressions of hepatic CHOP, GPR87, NF-κB and mTOR. Histopathological examination revealed massive hepatocyte degeneration following HgCl2 administration. Treatment with Vit-E or/and Lac-B restored the normal levels of the previously mentioned parameters, as well as improved hepatic architecture.

CONCLUSION

Vit-E and Lac-B provided protective effect against HgCl2-induced hepatotoxicity via reduction of oxidative stress and inflammation, and downregulation of CHOP, GPR87, NF-κB and mTOR proteins' expressions.

Prophylactic supplementation with selenium alters disposition of mercury in aged rats

Mercury (Hg) is a prevalent environmental toxicant to which older individuals are particularly susceptible. Selenium (Se) has been used as an antidote following exposure to Hg. However, little is known about the effect of prophylactic supplementation with Se on the handling of Hg. The current study was designed to test the hypothesis that oral pre-treatment with Se alters the corporal disposition of Hg and reduces the risk of Hg-induced toxicity. Young and aged rats were gavaged for 10 days with sodium selenite or saline. On day 11, rats were injected intravenously with 0.5 μmol HgCl₂·kg^-1·2 mL^-1 normal saline. After 24 h, rats were euthanized and organs and tissues were harvested for determination of Hg content. Accumulation of Hg in the kidney was reduced significantly by pre-treatment with Se in both young and aged rats. In the renal cortex, the magnitude of the reduction was greater in aged rats than in young rats but in the outer stripe of the outer medulla, the magnitude of the reduction was similar between groups of rats. Urinary excretion of Hg was also reduced in rats pre-treated with Se. In contrast, the hepatic and hematologic burden of Hg increased in rats pre-treated with Se. Fecal excretion of Hg was decreased significantly by pre-treatment with Se in young rats but not in aged rats. These data suggest that prophylactic supplementation with Se alters the corporal disposition of Hg in a way that may reduce Hg-induced toxicity in target organs.

NLRP3 inflammasome is involved in the mechanism of mitigative effect of selenium on lead-induced inflammatory damage in chicken kidneys

Lead (Pb) is a kind of widespread toxic environmental pollutant which can cause harm to organisms. Selenium (Se) has the property of mitigating Pb toxicity through decreasing oxidative stress and inflammation caused by Pb. Nucleotide-binding domain, leucine-rich-containing family, and pyrin-domain containing-3 (NLRP3) inflammasome involve in inflammation process. However, the effect of NLRP3 inflammasome in heavy metal-caused animal damage remains unknown. This research aimed to explore the mechanism of mitigative role of Se on Pb-caused renal inflammatory injury in chickens. One-week-old male chickens were provided a standard diet and drinking water, a standard diet added with 1 mg kg^-1 of Se and drinking water, a standard diet and drinking water added with 350 mg L^-1 Pb, and a standard diet added with 1 mg kg^-1 Se and drinking water added with 350 mg L^-1 Pb. On the 4th, 8th, and 12th weeks, serum was used to measure creatinine (CREA) and uric acid (UA) contents, and kidneys were used to measure Se and Pb concentrations, histological structure, oxidative stress indicators, relative expressions of cytokines, and inflammatory factors. The results showed that Pb accumulated, Se concentration decreased, CREA and UA contents increased, and renal injury occurred in Pb-treated chicken kidneys. Excess Pb increased MDA content and the expressions of IL-1β, IL-6, IL-17, NLRP3, caspase-1, NF-κB, COX-2, TNF-α, and PTGEs and decreased GSH content, GPx and SOD activities, and IFN-γ expression in the chicken kidneys. Se administration alleviated the aforementioned changes. In addition, toxic effect of Pb on the chicken kidneys was time-dependent. NLRP3 inflammasome, caspase-1, and IL-1β may be sensitive indicators in Pb-induced chicken kidney inflammatory damage. In conclusion, NLRP3 inflammasome took part in antagonistic role of Se against Pb-caused inflammation via changing oxidative stress indicators, cytokines, and inflammation-related genes in the chicken kidneys.

Abatement of the dysfunctional hypothalamic-pituitary-gonadal axis due to ciprofloxacin administration by selenium in male rats

The present study examined the influence of selenium on ciprofloxacin-mediated reproductive dysfunction in rats. The research design consisted of five groups of eight animals each. The rats were administered 135 mg/kg body weight of ciprofloxacin per se or simultaneously with selenium at 0.25 and 0.5 mg/kg for 15 uninterrupted days. Antioxidant and inflammatory indices were assayed using the testes, epididymis, and hypothalamus of the animals after sacrifice. Results revealed that ciprofloxacin treatment per se interfered with the reproductive axis as demonstrated by diminished serum hormonal levels, sperm quality, and enzymatic indices of testicular function, which were, however, abrogated following selenium co-treatment. Besides this, administration of selenium attenuated the depletion of glutathione level, inhibition of catalase, superoxide dismutase, glutathione-S-transferase and glutathione peroxidase activities with a concomitant reduction in reactive oxygen and nitrogen species, and lipid peroxidation in ciprofloxacin-treated in rats. Selenium treatment also mitigated ciprofloxacin-mediated elevation in nitric oxide level and of myeloperoxidase activity as well as histological lesions in the animals. Overall, selenium attenuated impairment in the male reproductive axis due to ciprofloxacin treatment through abatement of inflammation and oxidative stress in rats.

Treatment of oxidative stress, apoptosis, and DNA injury with N-acetylcysteine at simulative pesticide toxicity in fish

Pesticide toxicities are common in aquatic ecosystems and affects aquatic livings negative. Therefore, it is important to strengthen the antioxidant system in aquatic organisms and to protect the organisms against these toxic chemicals. In this study, the simulative toxicity was established to the fish then the healing process was followed. For this purpose, rainbow trout Oncorhynchus mykiss exposed to cypermethrin and left to the recovery process with either N-acetyl cysteine (an antioxidant, 0.5 mM-1.0 mM concentrations) or no intervention (self-healing) for 96 h. In this context, paraoxonase (PON), arylesterase (AR), myeloperoxidase (MPO), antioxidant enzymes (SOD, CAT, GPx), acetylcholinesterase (AChE) activities as well as MDA, caspase-3 and 8-OHdG levels were measured in fish gills, liver and kidney tissues. In addition, trace element tests were performed in the tissues sampled for each group. At the result of pesticide exposure, SOD, CAT, GPx, PON, AR and AChE activities were increased but MDA, MPO, caspase-3 and 8-OHdG levels were decreased in N-acetyl cysteine (NAC) treated groups in all tissues compared to self-healing group (p < 0.05). When the element analysis of the samples was examined, tissue-based differences were observed significantly in all application groups (p < 0.05). Considering the results of the study, it was found that NAC administration at high concentration (1.0 Mm NAC) was more effective on pesticide toxicity. It was concluded that the most sensitive tissue was the kidney.

Mercury toxicity in pregnant and lactating rats: zinc and N-acetylcysteine as alternative of prevention

This study evaluated the toxic effects of inorganic mercury (Hg) in pregnant and lactating rats, as well as the possible protective effect of zinc (Zn) and N-acetylcysteine (NAC). Pregnant and lactating rats were pre-treated with ZnCl₂ (27 mg/kg) and/or NAC (5 mg/kg) and after 24 h, they were exposed to HgCl₂ (10 mg/kg). Animals were sacrificed 24 h after Hg exposure, and biochemical tests and metal determination were performed. Regarding pregnant rats, Hg exposure caused kidney, blood, and placenta δ-aminolevulinic acid dehydratase (δ-ALA-D) activity inhibition, and the pre-treatments showed a tendency of protection. Moreover, all the animals exposed to Hg presented high Hg levels in the kidney, liver, and placenta when compared with control group. Pregnant rats pre-exposed to Zn (Zn-Hg and Zn/NAC-Hg groups) presented an increase in hepatic metallothionein levels. Therefore, lactating rats exposed to Hg presented renal and blood δ-ALA-D inhibition; the pre-treatments showed a tendency to prevent the renal δ-ALA-D inhibition and prevented the blood δ-ALA-D inhibition caused by Hg. Lactating rats exposed to Hg presented high Hg levels in the kidney and liver. These results showed that 10 mg/kg of HgCl₂ causes biochemistry alterations in pregnant and lactating rats, and Zn and NAC present promising results against these damages.

The role of endoplasmic reticulum stress in renal damage caused by acute mercury chloride poisoning

Acute mercury chloride (HgCl₂) poisoning may lead to kidney injury, but the underlying mechanism remains largely unknown. Endoplasmic reticulum (ER) stress plays a role in some heavy metal poisoning. Whether it mediates kidney injury in acute HgCl₂ poisoning remains unknown. In this study, we examined the kidney injury and the corresponding ER stress in the mouse model of different doses of acute HgCl₂ poisoning. To further confirm the role of ER stress, we tested the effects of its chemical chaperone [4-phenylbutyric acid (4-PBA)]. The results revealed that acute HgCl₂ poisoning caused more severe kidney injury with dose on and activated ER stress, as indicated by increased expression of GRP78 and CHOP. Inhibition of ER stress restored the functional and morphological changes of kidneys, and partly attenuated renal tubular epithelial cell apoptosis. In summary, ER stress contributes to the acute kidney injury following HgCl₂ poisoning, and inhibition of ER stress may alleviate the kidney injury via reducing apoptosis.

N-Acetyl Cysteine Modulates the Inflammatory and Oxidative Stress Responses of Rescued Growth-Arrested Dental Pulp Microtissues Exposed to TEGDMA in ECM

Dental pulp is exposed to resin monomers leaching from capping materials. Toxic doses of the monomer, triethyleneglycol dimethacrylate (TEGDMA), impact cell growth, enhance inflammatory and oxidative stress responses, and lead to tissue necrosis. A therapeutic agent is required to rescue growth-arrested tissues by continuing their development and modulating the exacerbated responses. The functionality of N-Acetyl Cysteine (NAC) as a treatment was assessed by employing a 3D dental pulp microtissue platform. Immortalized and primary microtissues developed and matured in the extracellular matrix (ECM). TEGDMA was introduced at various concentrations. NAC was administered simultaneously with TEGDMA, before or after monomer addition during the development and after the maturation stages of the microtissue. Spatial growth was validated by confocal microscopy and image processing. Levels of inflammatory (COX2, NLRP3, IL-8) and oxidative stress (GSH, Nrf2) markers were quantified by immunoassays. NAC treatments, in parallel with TEGDMA challenge or post-challenge, resumed the growth of the underdeveloped microtissues and protected mature microtissues from deterioration. Growth recovery correlated with the alleviation of both responses by decreasing significantly the intracellular and extracellular levels of the markers. Our 3D/ECM-based dental pulp platform is an efficient tool for drug rescue screening. NAC supports compromised microtissues development, and immunomodulates and maintains the oxidative balance.

Response of selenoproteins gene expression profile to mercuric chloride exposure in chicken kidney

Kidney is a primary target organ for mercuric chloride (HgCl₂) toxicity. Selenium (Se) can exert antagonistic effect on heavy metals-induced organ toxicity by regulating the expression of selenoproteins. The objective of this study was to investigate the effect of HgCl₂ on the gene expression of selenoproteins in chicken kidney. Sixty male Hyline brown chickens were randomly and evenly divided into two groups. After acclimatization for one week, chickens were provided with the standard diet as well as non-treated water (CON group), and standard diet as well as HgCl₂-treated water (250 ppm, HgCl₂ group). After seven weeks, kidney tissues were collected to examine the mRNA expression levels of 25 selenoproteins genes and protein expression levels of 4 selenoproteins. Moreover, correlation analysis and principal component analysis (PCA) were used to analyze the expression patterns of 25 selenoproteins. The results showed that HgCl₂ exposure significantly decreased the mRNA expression of Glutathione peroxidase 1 (GPX1), GPX4, Thioredoxin reductase 2 (TXNRD2), Iodothyronine deiodinase 1 (DIO1), Methionine-Rsulfoxide reductase 1 (SELR), 15-kDa selenoprotein (SEP15), selenoprotein I (SELI), SELK, SELM, SELN, SELP, SELS, SELT, SELW, and SEPHS2. Meanwhile, HgCl₂ exposure significantly increased the mRNA expression of GPX3, TXNRD1, and SELU. Western blot analysis showed that the expression levels of GPX3, TXNRD1, SELK, and SELN were concordant with these mRNA expression levels. Analysis results of selenoproteins expression patterns showed that HgCl₂-induced the main disorder expression of selenoproteins with antioxidant activity and endoplasmic reticulum resident selenoproteins. In conclusion, selenoproteins respond to HgCl₂ exposure in a characteristic manner in chicken kidney.

Methylmercury Poisoning Induces Cardiac Electrical Remodeling and Increases Arrhythmia Susceptibility and Mortality

This study aims to investigate the cardiac electrical remodeling associated with intoxication by methylmercury (MeHg). We evaluated the chronic effects of MeHg on in vivo electrocardiograms and on ex vivo action potentials and depolarizing (I_Ca-L) and repolarizing (I_to) currents. The acute effect of MeHg was evaluated on HEK293 cells expressing human ERG, Kv4.3 and KCNQ1/KCNE1 channels. Chronic MeHg treatment increased QTc and T_peak–T_end interval duration, prolonged action potential duration and decreased amplitude of I_to and I_Ca-L. In addition, heterologously expressed I_hKv4.3, I_hERG or I_hKCNQ1/KCNE1 decreased after acute exposure to MeHg at subnanomolar range. The introduction of the in vitro effects of MeHg in a computer model of human ventricular action potentials triggered early afterdepolarizations and arrhythmia. In conclusion, cardiac electrical remodeling induced by MeHg poisoning is related to the reduction of I_to and I_Ca-L. The acute effect of MeHg on hKv4.3; hERG and hKCNQ1/KCNE1 currents and their transposition to in silico models show an association between MeHg intoxication and acquired Long QT Syndrome in humans. MeHg can exert its high toxicity either after chronic or acute exposure to concentrations as low as picomolar.

Protective effect of rutin on mercuric chloride-induced reproductive damage in male rats

This study investigated the effects of rutin against reproductive damage caused by toxic mercury in male rats. Thirty-five Sprague Dawley rats were used. Control group was injected with saline for 7 days. The rutin-100 group received 100 mg/kg/b.w. rutin for 7 days. Mercuric chloride (HgCl₂ ) group received 1.23 mg/kg/b.w. of HgCl₂ for 7 days. Mercury chloride + rutin-50 group received 50 mg/kg/b.w. rutin and HgCl₂ 1.23 mg/kg/b.w. for 7 days. HgCl₂  + rutin-100 group received 100 mg/kg/b.w. rutin and HgCl₂ 1.23 mg/kg/b.w. for 7 days. It was detected that HgCl₂ treatment increased malondialdehyde (MDA) levels, tumour necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2) expressions, necrosis and degeneration of spermatogonium, dead and abnormal sperm percentages; tubular walls thinning; and decreased antioxidant enzyme activities and sperm motility. It was determined that rutin application reduced testicular damage caused by HgCl₂ . In conclusion, rutin administration may treat HgCl₂ toxicity in testes.

Inorganic mercury-induced MIP-2 expression is suppressed by N-acetyl-L-cysteine in RAW264.7 macrophages

Macrophages play an important role in neurotoxicity caused by methylmercury exposure through inflammatory responses. Methylmercury is known to demethylate to inorganic mercury in the brain, and macrophages are likely to be involved in this process. However, the inflammatory responses of macrophages against exposure to inorganic mercury are unclear. In the present study, inflammatory cytokine expression profiles were examined in the presence of non-toxic doses of inorganic mercury (Hg²⁺) using RAW264.7 macrophages, focusing on the expression of C-X-C motif chemokine 2 (MIP-2)/platelet-derived growth factor-inducible protein KC (KC) and C-C motif chemokine 12 (MCP-5). Furthermore, the suppressive effect of N-acetyl-L-cysteine (NAC) on inorganic mercury-induced MIP-2 expression was also examined. Inorganic mercury-induced mRNA expression was measured using reverse transcription-quantitative PCR. The mRNA expression of MIP-2 and MCP-5 was significantly upregulated by exposure to 20 µM Hg²⁺ (non-toxic levels), but not that of KC. The suppressive effect of NAC on these cytokine expression levels was examined by its addition to the culture medium together with Hg²⁺ (co-treatment), and pre- and post-treatments in which the cells were treated with NAC before and after Hg²⁺ exposure, respectively. Hg²⁺-upregulated MIP-2 expression was suppressed by NAC regardless of the time sequence of the treatment, suggesting that the suppressive role of NAC in Hg²⁺-induced inflammation manifests as a possible chelator and antioxidant/reactive oxygen species scavenger.

Rutin ameliorates mercuric chloride-induced hepatotoxicity in rats via interfering with oxidative stress, inflammation and apoptosis

OBJECTIVE

Mercury is a global environmental pollutant and is responsible for several organ pathophysiology including oxidative stress-induced liver disorders. Therefore, the present study was conducted to evaluate the potential ameliorative effects of rutin on mercury chloride (HgCl₂)-induced hepatotoxicity in adult male rats.

METHODS

HgCl₂ was intraperitoneally injected at a dose of 1.23 mg/kg body weight for 7 days alone or in combination with the orally rutin (50 and 100 mg/kg body weight).

RESULTS

Rutin treatment significantly improved liver function tests [alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT)], and increased activities of antioxidant defense system [catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx)] and glutathione (GSH) content. The histological alterations and epidermal growth factor receptor (EGFR) expression in the HgCl₂-induced liver tissues were decreased by administration of rutin. Furthermore, rutin reversed the changes in levels of apoptosis and inflammation related proteins involving p53, Bcl-2 associated X protein (Bax), B-cell lymphoma-2 (Bcl-2), cytochrome c, nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNF-α), B-cell lymphoma-3(Bcl-3) and interleukin-1β (IL-1β), and inhibited p38α mitogen-activated protein kinase (MAPK) and cysteine aspartate specific protease-3 (caspase-3) activations.

CONCLUSION

The data of the present study suggest that rutin effectively suppress HgCl₂-induced hepatotoxicity by ameliorating oxidative stress, inflammation and apoptosis.

Efficacy of Ozone and Selenium Therapy for Alcoholic Liver Injury: An Experimental Model

BACKGROUND/AIM

Alcoholic liver disease is an important health problem which is reversible during early stages of liver damage, but becomes permanent with time. Nowadays, many studies focus on various agents that prevent, reduce or slow the progression of the toxic effects of alcohol. In our study, we investigated the efficiency of ozone and selenium against oxidative damage in a model of alcohol-induced liver damage.

MATERIALS AND METHODS

Forty-eight female Wistar Albino rats between 4 and 6 months of age and weighing 190-250 g were included in the study and were used as models of alcohol liver damage. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), serum and tissue total oxidant levels, serum and tissue total antioxidant levels, and the histopathological evaluation of the liver were performed in 8 groups.

RESULTS

In the statistical analysis, it was observed that ozone and/or selenium therapies decreased the AST levels. Total oxidant and antioxidant serum levels were found to vary in serum and tissue. Ozone and/or selenium therapies decreased liver damage, according to histopathological findings.

CONCLUSION

Through ozone and/or selenium therapies, less damage was observed histopathologically compared to the alcohol group. It is thought that the results of our study can be used in individual treatments following confirmation of liver damage in alcoholic patients.

L-α-Phosphatidylcholine attenuates mercury-induced hepato-renal damage through suppressing oxidative stress and inflammation

The potential ameliorative effects of L-α-phosphatidylcholine (PC) against mercuric chloride (HgCl₂)-induced hematological and hepato-renal damage were investigated. Rats were randomly allocated into four groups (n = 12): control, PC (100 mg/kg bwt, intragastrically every other day for 30 consecutive days), HgCl₂ (5 mg/kg bwt, intragastrically daily), and PC plus HgCl₂. Hematological and hepato-renal dysfunctions were evaluated biochemically and histopathologically. Hepatic and renal oxidative/antioxidative indices were evaluated. The expression of proinflammatory cytokines (tumor necrosis factor-α and interleukin-6) was also detected by ELISA. HgCl₂ significantly increased serum aminotransferases (ALT, AST), urea, and creatinine levels that are indicative of hepato-renal damage. HgCl₂ also induced a significant accumulation of malondialdehyde (+ 195%) with depletion of glutathione (- 43%) levels in the liver and renal tissues. The apparent hepato-renal oxidative damage was associated with obvious organ dysfunction that was confirmed by impairments in the liver and kidney histoarchitecture. Furthermore, HgCl₂ significantly attenuated the expression of proinflammatory cytokines named tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Conversely, PC treatment attenuated these effects, which improved the hematological and serum biochemical alternations, reduced the oxidative stress and proinflammatory cytokine levels, and ameliorated the intensity of the histopathological alterations in livers and kidneys of HgCl₂-treated rats. It could be concluded that PC displayed potential anti-inflammatory and antioxidant activities against HgCl₂-induced hepato-renal damage via suppression of proinflammatory cytokines and declining oxidative stress.

Neurochemical dysfunction in motor cortex and hippocampus impairs the behavioral performance of rats chronically exposed to inorganic mercury

Chronic exposure to mercury chloride (HgCl₂) has been shown to promote oxidative stress and cell death in the central nervous system of adult rats displaying motor and cognitive impairments. However, there are no investigations about neurochemical function after this type of exposure in rodents that may be associated with those behavioral changes already reported. Thus, the aim of this study was to analyze glutamatergic and GABAergic dysfunctions in the motor cortex and hippocampus of adult rats, in a model of chronic exposure to HgCl₂ in. Twenty rats were exposed to a daily dose of 0.375 mg/kg for 45 days. After this period, they were submitted to motor and cognitive functions tests and euthanized to collect the motor cortex and hippocampus for measurement of mercury (Hg) levels in the parenchyma and neurochemical assays for analysis of glutamatergic and GABAergic functions. It was observed that chronic exposure to HgCl₂ promoted increase in total Hg levels in these two brain areas, with changes in glutamatergic transport, but without changes in GABAergic transport. Functionally this model of exposure caused the decrease of the spontaneous motor locomotion and in the process of learning and memory. In this way, our results provide evidences that glutamatergic neurochemical dysfunction can be pointed out as a strong causal factor of motor and cognitive deficits observed in rats exposed to this HgCl₂.

Selenium and zinc protections against metal-(loids)-induced toxicity and disease manifestations: A review

Metals are ubiquitous in the environment due to huge industrial applications in the form of different chemicals and from extensive mining activities. The frequent exposures to metals and metalloids are crucial for the human health. Trace metals are beneficial for health whereas non-essential metals are dangerous for the health and some are proven etiological factors for diseases including cancers and neurological disorders. The interactions of essential trace metals such as selenium (Se) and zinc (Zn) with non-essential metals viz. lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg) in biological system are very critical and complex. A huge number of studies report the protective role of Se and Zn against metal toxicity, both in animal and cellular levels, and also explain the numerous mechanisms involved. However, it has been considered that a tiny dyshomeostasis in the metals/trace metals status in biological system could induce severe deleterious effects that can manifest to numerous diseases. Thus, in this particular review, we have demonstrated the critical protection mechanism/s of Se and Zn against Cd, Pb, As and Hg toxicity in a one by one manner to clarify the up-to-date findings and perspectives. Furthermore, biomolecular consequences are comprehensively presented in light of particular cellular/biomolecular events which are somehow linked to a subsequent disease. The analyzed reports support significant protection potential of Se and Zn, either alone or in combination with other agents, against each of the abovementioned non-essential metals. However, Se and Zn are still not being used as detoxifying agents due to some unexplained reasons. We hypothesized that Se could be a potential candidate for detoxifying As and Hg regardless of their chemical speciations, but requires intensive clinical trials. However, particularly Zn-Hg interaction warrants more investigations both in animal and cellular level.

Gender differences in mercury-induced hepatotoxicity: Potential mechanisms

The accumulation of mercury in the liver causes hepatotoxicity. The organic anion transporter 3 (Oat3) and the multidrug-resistance associated protein 2 (Mrp2) are involved in the hepatic excretion of toxins and drugs and in the hepatic handling of mercury. The aim of this work was to study if there are gender-related differences in mercuric chloride (HgCl₂)-induced hepatotoxicity in rats. Total mercury levels and protein expressions of Oat3 and Mrp2 in liver samples were also assessed to clarify the mechanisms underlying mercury-induced liver damage in male and female rats. Control and HgCl₂-treated male and female Wistar rats were used. Hepatotoxicity was evaluated by plasma activity of transaminases and alkaline phosphatase, as well as by histopathological analysis. Oat3 and Mrp2 expression was assessed by immunoblotting. Female rats displayed a higher HgCl₂-induced hepatotoxicity than male rats as demonstrated by the higher alterations in the plasma markers of liver damage and in the histopathology. The sex-related differences observed in the hepatic damage can be explained by the higher accumulation of mercury in liver from female rats. In this connection, after mercury treatment the expression of Mrp2 decreased in both sexes and the expression of Oat3 decreased only in males. The decreased in Oat3 abundance in the hepatocytes membranes in mercury-treated males would limit the uptake of mercuric ions into the liver protecting them from mercury hepatotoxicity.

Combination of Selenomethionine and N-Acetylcysteine Alleviates the Joint Toxicities of Aflatoxin B1 and Ochratoxin A by ERK MAPK Signal Pathway in Porcine Alveolar Macrophages

Our previous studies showed that aflatoxin B1 (AFB1) and ochratoxin A (OTA) could trigger joint immune toxicity. Little is known about the combined effects of selenomethionine (SeMet) and N-acetylcysteine (NAC) on the joint toxicities of the two toxins. In this study, results showed that SeMet or NAC alone or in combination significantly alleviated the downswing of cell viability, glutathione production, and phagorytosis induced by AFB1 and OTA in porcine alveolar macrophages. The uptrend of lactate dehydrogenase activities, apoptosis, reactive oxygen species levels, and the relative mRNA of inflammatory cytokines triggered by the two toxins was decreased. Combination of them was more effective than single application. Knockdown of p38, c-JUN N-terminal kinase (JNK), or extracellular signal-regulated kinase (ERK) via use of the corresponding specific siRNA could alleviate the joint toxicities of AFB1 and OTA. However, the ERK but not p38 or JNK pathway was involved in the protection of SeMet and NAC against the immunotoxicity. In conclusion, combination of SeMet and NAC might be a new therapeutic orientation for preventing the joint toxicities induced by AFB1 and OTA.

Exposure to Inorganic Mercury Causes Oxidative Stress, Cell Death, and Functional Deficits in the Motor Cortex

Mercury is a toxic metal that can be found in the environment in three different forms – elemental, organic and inorganic. Inorganic mercury has a lower liposolubility, which results in a lower organism absorption and reduced passage through the blood–brain barrier. For this reason, exposure models that use inorganic mercury in rats in order to evaluate its effects on the central nervous system are rare, especially in adult subjects. This study investigated if a chronic exposure to low doses of mercury chloride (HgCl2), an inorganic form of mercury, is capable of promoting motor alterations and neurodegenerative in the motor cortex of adult rats. Forty animals were exposed to a dose of 0.375 mg/kg/day, for 45 days. They were then submitted to motor evaluation and euthanized to collect the motor cortex. Measurement of mercury deposited in the brain parenchyma, evaluation of oxidative balance, quantification of cellular cytotoxicity and apoptosis and density of mature neurons and astrocytes of the motor cortex were performed. It was observed that chronic exposure to inorganic mercury caused a decrease in balance and fine motor coordination, formation of mercury deposits and oxidative stress verified by the increase of lipoperoxidation and nitrite concentration and a decrease of the total antioxidant capacity. In addition, we found that this model of exposure to inorganic mercury caused cell death by cytotoxicity and induction of apoptosis with a decreased number of neurons and astrocytes in the motor cortex. Our results provide evidence that exposure to inorganic mercury in low doses, even in spite of its poor ability to cross biological barriers, is still capable of inducing motor deficits, cell death by cytotoxicity and apoptosis, and oxidative stress in the motor cortex of adult rats.

Beneficial effects of N-acetylcysteine on hepatic oxidative stress in streptozotocin-induced diabetic rats

Diabetes is one of the leading diseases worldwide and, thus, finding new therapeutic alternatives is essential. The development of non-alcoholic fatty liver disease is a notable diabetic complication. Therefore, antioxidant therapy became a leading topic in the world of diabetes research. The objective of this present study was to evaluate the effects of antioxidant N-acetylcysteine (NAC) administration on serum biochemical parameters and oxidative stress parameters in hepatic tissue of the diabetic rats. Thirty-two animals were divided in 4 groups (n = 8): G1, normal rats; G2, normal rats + NAC; G3, diabetic rats; and G4, diabetic rats + NAC. Diabetes was induced in diabetic groups through streptozotocin. NAC administration was effective in improving hyperglycemia and hypoinsulinemia, as well as reducing serum alanine-aminotransferase and urea, hepatic triglycerides accumulation, and oxidative stress biomarkers in the diabetic liver, as well as improving the activity of hepatic antioxidant enzymes. This effect was likely due to NAC’s ability of restoring intracellular glutathione, an important compound for the antioxidant defense, as well as due to NAC’s direct antioxidant properties. Thus, NAC administration was useful for reducing hepatic oxidative stress and decreased the deposit of triacylglycerols, minimizing diabetic hepatic damage, making it a promising therapeutic adjuvant in the future.

A critical review of selenium biogeochemical behavior in soil-plant system with an inference to human health

Selenium (Se) is an essential trace element for humans and animals, although controversial for different plant species. There exists a narrow line between essential, beneficial and toxic levels of Se to living organisms which greatly varies with Se speciation, as well as the type of living organisms. Therefore, it is crucial to monitor its solid- and solution-phase speciation, exposure levels and pathways to living organisms. Consumption of Se-laced food (cereals, vegetables, legumes and pulses) is the prime source of Se exposure to humans. Thus, it is imperative to assess the biogeochemical behavior of Se in soil-plant system with respect to applied levels and speciation, which ultimately affect Se status in humans. Based on available relevant literature, this review traces a plausible link among (i) Se levels, sources, speciation, bioavailability, and effect of soil chemical properties on selenium bioavailability/speciation in soil; (ii) role of different protein transporters in soil-root-shoot transfer of Se; and (iii) speciation, metabolism, phytotoxicity and detoxification of Se inside plants. The toxic and beneficial effects of Se to plants have been discussed with respect to speciation and toxic/deficient concentration of Se. We highlight the significance of various enzymatic (catalase, peroxidase, superoxide dismutase, ascorbate peroxidase, glutathione peroxidase) and non-enzymatic (phytochelatins and glutathione) antioxidants which help combat Se-induced overproduction of reactive oxygen species (ROS). The review also delineates Se accumulation in edible plant parts from soils containing low or high Se levels; elucidates associated health disorders or risks due to the consumption of Se-deficient or Se-rich foods; discusses the potential role of Se in different human disorders/diseases.

Impact of Childhood Malnutrition on Host Defense and Infection

The global impact of childhood malnutrition is staggering. The synergism between malnutrition and infection contributes substantially to childhood morbidity and mortality. Anthropometric indicators of malnutrition are associated with the increased risk and severity of infections caused by many pathogens, including viruses, bacteria, protozoa, and helminths. Since childhood malnutrition commonly involves the inadequate intake of protein and calories, with superimposed micronutrient deficiencies, the causal factors involved in impaired host defense are usually not defined. This review focuses on literature related to impaired host defense and the risk of infection in primary childhood malnutrition. Particular attention is given to longitudinal and prospective cohort human studies and studies of experimental animal models that address causal, mechanistic relationships between malnutrition and host defense. Protein and micronutrient deficiencies impact the hematopoietic and lymphoid organs and compromise both innate and adaptive immune functions. Malnutrition-related changes in intestinal microbiota contribute to growth faltering and dysregulated inflammation and immune function. Although substantial progress has been made in understanding the malnutrition-infection synergism, critical gaps in our understanding remain. We highlight the need for mechanistic studies that can lead to targeted interventions to improve host defense and reduce the morbidity and mortality of infectious diseases in this vulnerable population.

Curcuma longa Linn. extract and curcumin protect CYP 2E1 enzymatic activity against mercuric chloride-induced hepatotoxicity and oxidative stress: A protective approach

The present investigation has been conducted to evaluate the therapeutic potential of Curcuma longa (200mgkg^-1, po) and curcumin (80mgkg^-1, po) for their hepatoprotective efficacy against mercuric chloride (HgCl₂: 12μmolkg^-1, ip; once only) hepatotoxicity. The HgCl₂ administration altered various biochemical parameters, including transaminases, alkaline phosphatase, lactate dehydrogenase, bilirubin, gamma-glutamyl transferase, triglycerides and cholesterol contents with a concomitant decline in protein and albumin concentration in serum which were restored towards control by therapy of Curcuma longa or curcumin. On the other hand, both treatments showed a protective effect on drug metabolizing enzymes viz. aniline hydroxylase (AH) and amidopyrine-N-demethylase (AND), hexobarbitone induced sleep time and BSP retention. Choleretic, 1,1-diphenyl-2-picryl-hydrazil (DPPH)-free radical scavenging activities and histological studies also supported the biochemical findings. The present study concludes that Curcuma longa extract or curcumin has the ability to alleviate the hepatotoxic effects caused by HgCl₂ in rats.

Hg and Se exposure in brain tissues of striped dolphin (Stenella coeruleoalba) and bottlenose dolphin (Tursiops truncatus) from the Tyrrhenian and Adriatic Seas

In this study we analyzed Hg and Se concentrations in dolphin brain tissues of fifteen specimens of striped dolphin (Stenella coeruleoalba) and eight specimens of bottlenose dolphin (Tursiops truncatus) stranded in the Tyrrhenian and Adriatic Seas, in order to assess the toxicological risks associated with Hg exposure. High Hg concentrations were found in brain tissues of both analyzed specie (1.86-243 mg/kg dw for striped dolphin and 2.1-98.7 mg/kg dw for bottlenose dolphin), exceeding levels associated with marine mammals neurotoxicity. Althougth the results clearly suggest that the protective effects of Se against Hg toxicity occur in cetaceans' brain tissues, a molar excess of mercury with respect to selenium was found, particularly in adult specimens of Stenella coeruleoalba. On contrary, negligible neurotoxicological risks were found for Tursiops truncatus specimens, due to detoxification processes. Data obtained allowed to prove a more marked neurotoxicological risk for adult specimens of Stenella coeruleoalba in both Tyrrhenian and Adriatic Seas.

The aging kidney and the nephrotoxic effects of mercury

Owing to advances in modern medicine, life expectancies are lengthening and leading to an increase in the population of older individuals. The aging process leads to significant alterations in many organ systems, with the kidney being particularly susceptible to age-related changes. Within the kidney, aging leads to ultrastructural changes such as glomerular and tubular hypertrophy, glomerulosclerosis, and tubulointerstitial fibrosis, which may compromise renal plasma flow (RPF) and glomerular filtration rate (GFR). These alterations may reduce the functional reserve of the kidneys, making them more susceptible to pathological events when challenged or stressed, such as following exposure to nephrotoxicants. An important and prevalent environmental toxicant that induces nephrotoxic effects is mercury (Hg). Since exposure of normal kidneys to mercuric ions might induce glomerular and tubular injury, aged kidneys, which may not be functioning at full capacity, may be more sensitive to the effects of Hg than normal kidneys. Age-related renal changes and the effects of Hg in the kidney have been characterized separately. However, little is known regarding the influence of nephrotoxicants, such as Hg, on aged kidneys. The purpose of this review was to summarize known findings related to exposure of aged and diseased kidneys to the environmentally relevant nephrotoxicant Hg.

Sodium Selenite Protects Against Silver Nanoparticle-Induced Testicular Toxicity and Inflammation

Metal nanomaterials hold great potential and play an important role in consumer products. However, the increasing use of nanomaterials has raised concern over inadvertent exposure and potential risks for human health and the environment. Henceforth, in vivo testing of nanoparticles and protection against its toxicity is required. Using rat as an animal model, effect of sodium selenite (Se), an essential trace element, on rat testes exposed to silver nanoparticles (AgNPs) was evaluated. Male rats were treated with AgNPs (5 mg/kg/b.w) i/p or Se (0.2 mg/kg/b.w) by gavage. AgNP administration decreased Glutathione (GSH) levels and activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) and increased levels of malondialdehyde (MDA) and expression of interleukin-1 beta (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α). However, treatment with Se increased GSH levels and activities of SOD, CAT, and GPx compared with AgNP-treated group and decreased the level of MDA and inflammatory biomarkers significantly (p < 0.05) as compared with AgNP-treated group. Light microscopic analyses also revealed that AgNP induced histopathological changes in testes tissue. Further, protection by Se on biochemical results was confirmed by alleviation of the histopathological changes in the tissue. Results show the adverse effects of AgNPs on the male reproductive tract, particularly spermatogenesis, and suggest that Se possesses significant potential in reducing AgNP-induced testicular toxicity.

Protective effects of curcumin against mercury-induced hepatic injuries in rats, involvement of oxidative stress antagonism, and Nrf2-ARE pathway activation

Mercury (Hg) represents a ubiquitous environmental heavy metal that could lead to severe toxic effects in a variety of organs usually at a low level. The present study focused on the liver oxidative stress, one of the most important roles playing in Hg hepatotoxicity, by evaluation of different concentrations of mercuric chloride (HgCl₂) administration. Moreover, the protective potential of curcumin against Hg hepatotoxic effects was also investigated. Eighty-four rats were randomly divided into six groups for a three-days experiment: control, dimethyl sulfoxide control, HgCl₂ treatment (0.6, 1.2, and 2.4 mg kg^-1 day^-1), and curcumin pretreatment (100 mg kg^-1 day^-1) groups. Exposure of HgCl₂ resulted in acute dose-dependent hepatotoxic effects. Administration of 2.4 mg kg^-1 HgCl₂ significantly elevated total Hg, nonprotein sulfhydryl, reactive oxygen species formation, malondialdehyde, apoptosis levels, serum lactate dehydrogenase, and alanine transaminase activities, with an impairment of superoxide dismutase and glutathione peroxidase in the liver. Moreover, HgCl₂ treatment activated nuclear factor-E2-related factor 2-antioxidant response element (Nrf2-ARE) signaling pathway in further investigation, with a significant upregulation of Nrf2, heme oxygenase-1, and γ-glutamylcysteine synthetase heavy subunit expression, relative to control. Pretreatment with curcumin obviously prevented HgCl₂-induced liver oxidative stress, which may be due to its free radical scavenging or Nrf2-ARE pathway-inducing properties. Taking together these data suggest that curcumin counteracts HgCl₂ hepatotoxicity through antagonizing liver oxidative stress.

N-acetylcysteine and meso-2,3-dimercaptosuccinic acid alleviate oxidative stress and hepatic dysfunction induced by sodium arsenite in male rats

Environmental exposure to arsenic represents a serious challenge to humans and other animals. The aim of the present study was to test the protective effect of antioxidant N-acetylcysteine (NAC) either individually or in combination with a chelating agent, meso-2,3-dimercaptosuccinic acid (DMSA), against sodium arsenite oral toxicity in male rats. Five groups were used: control; arsenic group (orally administrated in a concentration of 2 mg/kg body weight [b.w.]); the other three groups were orally administrated sodium arsenite in a concentration of 2 mg/kg b.w. followed by either NAC (10 mg/kg b.w., intraperitoneally [i.p.]), DMSA (50 mg/kg b.w., i.p.) or NAC plus DMSA. Arsenic toxicity caused significant rise in serum aspartate aminotransferase, alanine aminotransferase and total bilirubin, and a significant decrease in total protein (TP) and albumin levels after 3 weeks of experimental period. In addition, arsenic-treated rats showed significantly higher arsenic content in liver and significant rise in hepatic malondialdehyde level. By contrast, sharp decreases in glutathione content and catalase and glutathione reductase activities were discernible. NAC and/or DMSA counteracted most of these physiologic and biochemical defects. NAC monotherapy was more effective than DMSA in increasing TP, while DMSA was more effective in decreasing alanine aminotransferase. The combined treatment was superior over monotherapies in recovery of TP and glutathione. Biochemical data were well supported by histopathological and ultrastructural findings. In conclusion, the combination therapy of NAC and DMSA may be an ideal choice against oxidative insult induced by arsenic poisoning.

Mercuric chloride induced hepatotoxic and hematologic changes in rats

This study focuses on investigating the possible protective effect of sodium selenite (Na2SeO3) and/or vitamin E against mercuric chloride (HgCl2)-induced hepatotoxicity in rat. Male rats were given HgCl2 (1 mg/kg body weight (bw)) and HgCl2 plus Na2SeO3 (0.25 mg/kg bw) and/or vitamin E (100 mg/kg bw) daily via gavage for 4 weeks. HgCl2-treated groups had significantly higher white blood cell and thrombocyte counts than the control group. Serum activities of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, γ-glutamyl-transferase, and lactate dehydrogenase significantly increased and serum levels of total protein, albumin, triglyceride, total cholesterol, and low-density lipoprotein cholesterol significantly decreased in the HgCl2-treated groups compared with control group. Malondialdehyde level significantly increased and superoxide dismutase, catalase, and glutathione peroxidase activities decreased in liver tissue of HgCl2-treated rats. Also, HgCl2 exposure resulted in histopathological changes. Supplementation of Na2SeO3 and/or vitamin E provided partial protection in hematological and biochemical parameters that were altered by HgCl2. As a result, Na2SeO3 and/or vitamin E significantly reduced HgCl2-induced hepatotoxicity, but not protected completely.

Effect of Selenium on the Levels of Cytokines and Trace Elements in Toxin-Mediated Oxidative Stress in Male Rats

Selenium is an essential cofactor in the key enzymes involved in cellular antioxidant defense. This study was designed to investigate the protective effects of selenium on mercury chloride (HgCl2)-induced toxicity. Male Wistar rats were randomly divided into four groups of six animals each. The first group was control; the second group was treated with mercuric chloride (HgCl2: 50 mg/kg/bw). The third group was treated with sodium selenite (Se 0.2 mg/kg/bw), and the fourth group received Se (0.2 mg/kg/bw) plus HgCl2 (50 mg/kg for 24 h). The influence of Se on mercury induced levels of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) and zinc, copper, and iron in serum of rats were observed. The serum MDA, SOD, zinc, and iron concentrations were found to be statistically different among the control and toxin-treated group. The serum levels of IL-6, IL-10, and TNF-α were also measured. There was a significant decrease in the levels of TNF-α, IL-6, and IL-10 in toxin-treated group II compared with that of the control group (p < 0.05). A significant increase in the serum levels of inflammatory cytokines IL-6, TNF-α, and IL-10 after administration of Se seemed to counteract some of the damage, as indicated by differences in the serum concentrations of major elements.

Oxidative Stress and Inflammation in Hepatic Diseases: Therapeutic Possibilities of N-Acetylcysteine

Liver disease is highly prevalent in the world. Oxidative stress (OS) and inflammation are the most important pathogenetic events in liver diseases, regardless the different etiology and natural course. N-acetyl-l-cysteine (the active form) (NAC) is being studied in diseases characterized by increased OS or decreased glutathione (GSH) level. NAC acts mainly on the supply of cysteine for GSH synthesis. The objective of this review is to examine experimental and clinical studies that evaluate the antioxidant and anti-inflammatory roles of NAC in attenuating markers of inflammation and OS in hepatic damage. The results related to the supplementation of NAC in any form of administration and type of study are satisfactory in 85.5% (n = 59) of the cases evaluated (n = 69, 100%). Within this percentage, the dosage of NAC utilized in studies in vivo varied from 0.204 up to 2 g/kg/day. A standard experimental design of protection and treatment as well as the choice of the route of administration, with a broader evaluation of OS and inflammation markers in the serum or other biological matrixes, in animal models, are necessary. Clinical studies are urgently required, to have a clear view, so that, the professionals can be sure about the effectiveness and safety of NAC prescription.

Protective Effects of Quercetin Against HgCl₂-Induced Nephrotoxicity in Sprague-Dawley Rats

Mercury is a well-known environmental pollutant that can cause nephropathic diseases, including acute kidney injury (AKI). Although quercetin (QC), a natural flavonoid, has been reported to have medicinal properties, its potential protective effects against mercury-induced AKI have not been evaluated. In this study, the protective effect of QC against mercury-induced AKI was investigated using biochemical parameters, new protein-based urinary biomarkers, and a histopathological approach. A 250 mg/kg dose of QC was administered orally to Sprague-Dawley male rats for 3 days before administration of mercury chloride (HgCl2). All animals were sacrificed at 24 h after HgCl2 treatment, and biomarkers associated with nephrotoxicity were measured. Our data showed that QC absolutely prevented HgCl2-induced AKI, as indicated by biochemical parameters such as blood urea nitrogen (BUN) and serum creatinine (sCr). In particular, QC markedly decreased the accumulation of Hg in the kidney. Urinary excretion of protein-based biomarkers, including clusterin, kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemoattractant protein-1 (MCP-1), tissue inhibitor of metalloproteinases 1 (TIMP-1), and vascular endothelial growth factor (VEGF) in response to HgCl2 administration were significantly decreased by QC pretreatment relative to that in the HgCl2-treated group. Furthermore, urinary excretion of metallothionein and Hg were significantly elevated by QC pretreatment. Histopathological examination indicated that QC protected against HgCl2-induced proximal tubular damage in the kidney. A TUNEL assay indicated that QC pretreatment significantly reduced apoptotic cell death in the kidney. The administration of QC provided significant protective effects against mercury-induced AKI.

Protective effect of pomegranate seed oil against mercuric chloride-induced nephrotoxicity in rat

PURPOSE

Heavy metals such as mercury can induce the generation of free radicals and oxidative stress which are associated with tissue injury. The present study was designed to evaluate the protective effect of pomegranate seed oil against HgCl2-induced nephrotoxicity.

METHODS

Twenty-four W/A adult rats were randomly divided into four groups. Group I received corn oil (1 mL/kg). Group II received HgCl2 (5 mg/kg) for 3 days. Group III and IV received PSO 0.4 mL/kg and 0.8 mL/kg, respectively one hour before HgCl2 administration for 3 days. Blood samples were taken by cardiac puncture and used for the measurement of urea and creatinine concentration. Twenty-hour-hour urine samples were collected to measure protein and glucose. The right kidney was fixed in formalin for histological examination and the left kidney was homogenized for measuring malondialdehyde (MDA) and total sulfhydryl groups.

RESULTS

Significant elevation of serum creatinine and urea levels as well as urine glucose and protein concentrations, a significant decrease in total thiol content and a significant increase in MDA levels in kidney homogenate samples were observed after administration of HgCl2 as compared with control group. PSO pretreatment resulted in a significant decrease in serum creatinine and urea levels as well as urine glucose and protein concentrations when compared with HgCl2 treated (group II). PSO also significantly reversed the HgCl2-induced depletion in thiol content and elevation in MDA content. Histological studies revealed milder kidney lesions in PSO treated groups (groups III and IV) compared to HgCl2 treated group.

CONCLUSION

Our results suggest that PSO has a protective effect against HgCl2-induced nephrotoxicity in rats.